To describe a technique to study the impact of disruption of SC structural features by assessing resulting ∆’s in pressure-dependent tissue responses. Sutures, viscoelastic and cannulas used intraluminally in SC microsurgery all dilate and damage SC structures, but techniques to study the effect on pressure-dependent tissue behavior have not been available.

Methods

Three SC locations L1, L2, L3 at CCO ostia were identified in a 7X y/o W/M. Locations were continuously imaged from the TM surface1 before, during and after a pulsed SC intraluminal balanced salt solution (BSS) bolus. The pulse volume and speed (250ml, 30ml/min) dilate SC enough to cause OCT documented internal disruption of SC structures. The pulsed bolus was delivered into SC through a 130 mm ID cannula using a perfusion pump. Prior to and following the bolus, OCT imaging of SC was done while maintaining static pressures of 0, 5, 10, 20, and 30 mm Hg. SC and CC area ∆s were assessed by manual delineation and automated measurements made using ImageJ software.

Results

As seen in Fig. 1 and Table 1, both before and after a pulsed bolus the SC and CCO areas significantly increased with increasing static pressures (p range <.001 to <.006). However, after the bolus, while maintaining identical static pressures, SC area increased at the same time CCO area decreased, i.e. at 30 mm Hg for (L1, L2, L3) SC area increased 87%, 79%, 9% while CCO area decreased -45%, -5%, -82% at the respective locations.

Conclusions

The described technique assesses the effect of intraluminal damage to SC & CC structures. Damage causes SC lumen size to increase while CC lumen size decreases. These results suggest SC dilation can result in altered pressure-dependent responses of the TM wall of SC and the collagenous tissues surrounding CCO. Since microsurgery procedures involving SC dilation can change the tissue configuration and responses to pressure, the changes may affect aqueous outflow by means independent of the procedures intended effects. Intraluminal procedures that dilate SC structures can result in altered tissue configuration and responses to pressure that may in themselves impact outflow resistance.